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AbstractConsiderations of purpose, feasibility, and statistical power, as well as internal, external, and construct validity, determine both the units of sample selection, randomization, treatment, and observation and the analytical model one uses.

The authors provide a historical review of developments in the methods of school-based evaluations of problem behavior prevention interventions. The design and statistical methodologies used in school-based intervention research have advanced tremendously over the past twenty years. Methods have improved for approaches to the randomization of whole schools, the choice of appropriate comparison or control groups, solutions when randomization breaks down, limiting and handling of variation in integrity of the intervention received, limiting biases introduced by data collection, awareness of the effects of intensive and long-term data collection, limiting and analysis of subject attrition and other missing data, approaches to obtaining parental consent for children to engage in research, design and analysis issues when only small numbers of schools are available or can be afforded, the choice of the unit of analysis, phases of research, optimizing and extending the reach of interventions, and differential effects in subpopulations. The authors conclude that sequential planning, timing, keeping up with methodological advances, publication of results, and accumulation of knowledge are all important in conducting high-quality school-based intervention research, and that the devil is in the details.

The authors provide a historical review of developments in the methods of school-based evaluations of problem behavior prevention interventions. The design & statistical methodologies used in school-based intervention research have advanced tremendously over the past twenty years. Methods have improved for approaches to the randomization of whole schools; the choice of appropriate comparison or control groups; solutions when randomization breaks down; limiting & handling of variation in integrity of the intervention received; limiting biases introduced by data collection, awareness of the effects of intensive & long-term data collection; limiting & analysis of subject attrition & other missing data; approaches to obtaining parental consent for children to engage in research; design & analysis issues when only small numbers of schools are available or can be afforded; the choice of the unit of analysis; phases of research; optimizing & extending the reach of interventions; & differential effects in subpopulations. The authors conclude that sequential planning, timing, keeping up with methodological advances, publication of results, & accumulation of knowledge are all important in conducting high-quality school-based intervention research, & that the devil is in the details. 144 References. [Reprinted by permission of Sage Publications Inc., copyright 2005 The American Academy of Political and Social Science.]

Nonprescription stimulant use is a high-risk behavior prevalent in the college population. To date, research on this substance use behavior lacks a comprehensive theoretical lens as well as geographical diversity. Guided by the Theory of Triadic Influence (TTI), multilevel (i.e., students within schools) modeling was used to analyze survey data from the Spring 2009 American College Health Association–National College Health Assessment II. We hypothesized that the behavior would be associated with ultimate underlying causes, distal predisposing influences, proximal immediate predictors, and immediate precursors found in the TTI's three streams of influence (i.e., intrapersonal, social situation/context, and sociocultural environment). In our sample ( N = 10,220 students; 18 schools), the mean prevalence of past-year use of prescription stimulants without a prescription was 10.70% (range across schools, 0.33%-20.04%). Our hypothesis regarding the multifaceted nature of the predictors of the behavior was supported. Implications for prevention efforts, limitations, and future research directions are discussed.

School-based prevention trials typically face large variations in school composition and levels ofpreintervention behavior. Such variations may inhibit efforts to maximize internal and external validity. This article presents a method for using school-level attributes in sample description and random assignment of schools to conditions. The utility of the archival data was examined using multivanate canonical techniques. The authors found that a small set of attributes could efficiently predict the observed school-level variations in smoking and other drug use. It is recommended that these attributes be used by other school-based studies to enhance experimen talfield studies.

Heterogeneity often exists among behavioral growth trajectories in a study population. In the evaluation of intervention effects for longitudinal randomized trials, it is informative to examine the impact of an intervention on subgroups characterized by different types of growth trajectories. This paper presents an application of growth mixture modeling to an ordinal-scale substance-use behavior outcome from the Aban Aya Youth Project (AAYP), a longitudinal preventive intervention trial targeting health-compromising behaviors among adolescents. Results suggested two classes of adolescent substance use growth trajectories: Class 1 (44.7% of the sample) started at a higher level and had a relatively shallow increase over time; Class 2 had a lower baseline level and a rapid increase over time. The intervention effectively reduced the rapid increase of substance use for the adolescents in the second class.

The multilevel thresholds of change model is used to analyze the effect of a smoking cessation intervention on stage of readiness to quit across a 2-year follow-up period. The intervention, targeted to females with high school or less education, consisted of a televised component and a written manual. Any exposure to the intervention had a significant effect on stages that precede quitting but not on quitting; participation in the intervention had significant effects at all levels of change, including quitting. The written component had a stronger independent effect than the televised component. Intervention effects were strongest within women who were initially precontemplative.